The present invention relates to a window washing installation for motor vehicles with a reservoir tank for the washing liquid and a feed pump, especially a vane-type pump, in which a suction pipe of the feed pump is inserted into the reservoir tank under interposition of a sealing member and protrudes sectionwise into the interior of the tank and in which an agitator disposed inside of the suction pipe extends approximately up to the free end of the suction pipe and is thereat directly in contact with the washing liquid.
In a known windshield washing installation (DE-GM No. 19 49 575), a gear pump is provided for the feed of the washing liquid which is inserted from above into an opening of the reservoir tank. A suction pipe for the pump unit extends approximately up to the bottom of the reservoir tank and is closed off at the end with a sieve insert whereby a clogging of the spray nozzles of the windshield washing installation is avoided. This prior art arrangement entails the disadvantage that such gear pumps are costly and require a large structural space.
For avoiding the aforementioned disadvantages, frequently vane-type pumps are therefore used which require less structural space and can be manufactured in a more economic manner. A rotating agitator which is provided in these vane-type pumps inside of the suction pipe, protrudes beyond the suction pipe end by a slight amount. Furthermore, apertures open in the downward direction and diametrally arranged at the suction pipe end are provided so that the end area of the agitator has direct contact with the washing liquid and the vane-type pump operates self-priming.
The problem occurs in practice with windshield washing installations equipped with vane-type pumps that the spray nozzles become clogged up by contaminations or small particles contained in the washing liquid (for example, cleaning tablets) because a direct closing off of the suction pipe end by means of a sieve insert is not possible for functioning reasons. For if one were to close off the suction pipe end directly with a sieve insert, then the agitator would no longer have a direct contact with the washing liquid and an air cushion would be formed at the agitator end which brings about that the feed pump no longer operates self-priming.
It is the object of the present invention to undertake in a window washing installation with a self-priming vane-type pump such measures that a clogging of the spray nozzles is avoided together with good functioning of the vane-type pump.
The underlying problems are solved according to the present invention in that a lower end area of the suction pipe is surrounded by a sieve element.
The principal advantages achieved with the present invention reside in that by the arrangement of a sieve element surrounding the lower end area of the suction pipe and locally provided with sieve inserts, on the one hand, a clogging of the spray nozzles is avoided and in that, on the other, the self-priming action of the vane-type pump is always assured because the free end of the agitator is continuously in direct contact with the washing liquid. The sieve element represents a component which can be manufactured in a simple and economic manner. A simple and rapid assembly of the sieve element and of the feed pump is realized by a clamping-type fastening arrangement of the sieve element at the sealing body. Additionally, the sieve element is readily interchangeable.